Though there are many Instructables on some aspect of how to make circuit boards, this one is different. It's an instructable on how to make the things you need to make circuit boards, specifically, a flamboyant business card toy. Over the past six months I have set up fairly complete printed circuit board fabrication lab in my apartment, cheaply and safely, and I intend to cover all aspects of the process, from start to finish. Some of it you may have seen before, but here it is all in one place, with references.

All in all, I had to design and build an airtight etch tank out of laser cut acrylic, an SMD vacuum pickup tool, a reflow oven and temperature controller, refine the toner transfer process with a modified laminator, build a custom programming jig, and of course design, program and build from scratch every aspect of the thing I did all this for in the first place: my business card. In the end it was well worth the time to have the ability to make circuit boards appear in my hands in an evening.

The Business Card
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The POV Business Card uses the classic persistence of vision optical illusion to flash your name and number in midair as you wave the card. Based on the PIC12F508, an 8-pin 6 I/O ultra-low cost microcontroller, it is entirely surface mount and extremely thin- it uses PCB laminate that is as thin as a standard business card. And at roughly $2 apiece in parts, depending on how good you are at sourcing components, they are cheap enough to hand out (to the right people).

But why go to all this trouble simply to make something to give away to someone I just met? Why not just have them printed up in an afternoon for less than 10 bucks at Kinko's? Why, because I want a card that would not get thrown out. A card that would embody exactly what I do, instead of clumsily trying to sum it up in an clever job title. A card that would get me places.

The Scenario
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Picture the following scenario, if you will: you have just met someone who you need to know. In actual fact, they need to know you. Having exchanged introductions, "The Man," complete with dark suit and power tie, casually hands you his cloned, company-issue business card.

"Here's my card," he grins, knowing that you will impressed by his Ownership Of Card, or at least his Power Over Someone Who Owns An Embossing Machine .

Probably he expects to see you to scribble your number on a torn scrap of paper. But when you reach into your pocket and pull out your card, certainly he doesn't expect to see...your name glowing in midair, floating before his very eyes!

"It's called persistence of vision," you say, as you hand him your card. "I make these in my basement. From scratch."

You didn't even need to say another word; anything more would just be gloating. You can see the look in his eyes; he's already sold.

"Look at that subtle off-white coloring. The tasteful thickness of it. Oh my God, it even has a watermark."
- Patrick Bateman, American Psycho

Disclaimer: I should note here that this Instructable involves a lot of things that could be dangerous if done without caution and informed planning, including fire hazards, risk of electrocution in various horrible ways, handling of nasty chemicals, and very toxic fumes. This one really has it all, folks. So be safe!

Just curious as to where you sourced the bubbler wand; whether a standard pet shop aquarium wand will do or if you need something a bit more robust! Also, would there be anything stopping you from drilling a row of holes in a standard acrylic tube and chemically welding that in directly instead?

I got that online, but I wouldn't recommend it. The acid embrittled the bubble wand I had pretty rapidly. Acrylic rod would would work great, certainly better. We just need aeration, so lots of fine holes drilled in a tube would be perfect. Good idea actually, I hadn't thought of that.

Hmm, I guess concentrated acid isn't a very popular substrate for aquarium fish ; -)

I wonder if there is a non insidiously tedious way of drilling lots of tiny holes in acrylic round rod. Could it be done on a laser cuter with a small enough kerf somehow (I don't have much experience with them) ?

I have been using an electric skillet set to 350-375 and just moving the boards off to a bit of wood as soon as the solder paste all melts. I think as long as your components sink heat at about the same rate that is an easier approach. I did have problems with some boards with large-ish surface mount caps. The LEDs might have melted before the caps were soldered. I solve that problem by using the hot plate in two passes.

Do you think there is a danger with my method of cooling too fast and having some ill effect? It sure is easier.

The ideal reflow lasts peaks only for a few seconds. Take a look at the reflow curve in step 11. Of course there's a danger; theoretically and practically, the lifetime of the components will be compromised. The question is, by how much, and is it worth your time?

If you are making a thousand of something to tight tolerances, then the failure rate and inconsistency are unacceptable, and it's worth the time. If you are making 10 of a thing, and have the time to QA every one, then the skillet is probably easier. If it works, it works.

My setup is probably overkill for most home SMD projects. I'd even say it was overkill for my projects. :) As it's been said before, overkill is a way of life.

I find a zip top bag with a needle hole in the corner works great for applying solder paste. If you do big runs, a stencil probably saves time. For a few boards at a time I think I spent less total time and effort with the "icing" method. A suitably sized needle on a syringe is also said to work well.

in the Pic12F508/509/16f505, you want page 24, section 4.5. The option register sets up the internal timer and "wake up on pin change" functions. They are useful functions, but not used in this application. In this case, these settings are mostly there just to disable those features.

I live in Ireland, and, for the most part, we don't have Toaster Ovens (Actually, when I saw the picture, I thought it was a Microwave, which could have ended badly). Could you recommend an equivalent appliance I could use? Cheers.

Hey, Argos do actually sell toaster ovens (search on their website), although they only go up to 230C (allegedly - the picture actually shows 400F as the max, so may not even be 230C). I am quite interested in picking up a cheap toaster oven for some SMT work, if you have found anything workable in Ireland please let me know!

That's a weird question! I have no idea what the equivalent is over there. Lots of things would work; it just needs a metal enclosure and some kind of heating element. The risk is always how safe you could make something that heats to up to 300 C. What we call a toaster oven is capable of that just as a matter of course, and so is very safe.

You might be able to take a regular vertical toaster with side heating elements and place it on it's side. I don't know how hot those can get, but it may be close. It would need to be sealed with a door somehow. And you'd need to find out what the regular operating temperature and wattage was so you didn't exceed that and start a fire.

Also, if you don't need your design in massive quantities, you can just go over the board with a hot air soldering gun and get similar results. Even a regular pen type soldering iron works, with practice.

You mean how do we? The magic of the oven grill. Same principle as the above, only attached to an oven and a hob, which would make the whole thing terribly awkward and expensive to use as a reflow solder oven. Basically, the Toaster Oven above is to the Double Oven, what the Hotplate is to the hob.

Interesting. Here in USA we can buy one oven toaster like that in hundreds of department stores, like WalMart, Target, etc. They ALL are manufactured in China and you can buy then from 10 to 40 US Dollars. If you have electric stove, probably you may have available to sell the heating elements. Here we use a coiled resistance, electrically isolated, that heat to a point (if you want) to get really red and heat the pan over it. The pan really sits over the element. There 3 or 4 sizes of those heating elements, the second size, the most common around, is for 900W, if I remember well. They feed on 220Vac. In the past I build a SMD reflow solder oven using a toaster, but I was thinking to build another from scratch, stainless steel box, thermal insulation another box inside, fans, a sliding tray for the SMD boards, may be even a metalic belt for automation. Using those stove elements is easy, just one on top, another on bottom, the PCB in middle, 20 to 30mm distant from the heaters. The oven I build 3 to 4 years ago, you may find it at http://www.ustr.net/smt/oven.htm and http://www.ustr.net/smt/ . My process is much simpler than the posted here, since I use a microcontroller already programmed with the temperature profiles and the temperature is captures from a real small circuit board inside the oven, so it is not "air temperature", is an electronic circuit board temperature. Cost much less, since all the electronic control is made with less than $10. One day I need to publish that circuit and software.

I am working on my own card and encountered a problem with Hi-Tech C version 9.81. For some reason they do not have a declaration for "TRIS" in the header files. They will probably fix soon but in the meantime you just add this declaration before the main body of the code:

There's always something... Yes, I forgot to mention that the default device specific header files are sometimes lacking. I also had some problems when they changed their formatting on legacy devices for the PIC12F508/509 in the latest version of MPLAB. Thanks for catching that!

Out-friggin'-standing! This is the most detailed, best-written instructable I've read so far, and now my undisputed favorite.

I've never done any surface mount work myself, but you've inspired me to rescue my electronics stuff from the yard sale pile and give it a shot. I'd maybe like to make a card that has a snap-off portion that will reveal a tinned connector that plugs into a USB port and has some digitally stored goodies, like a copy of my resume and some pics and videos of me doing my stuff. Probably too expensive and complicated to be practical, but it would sure be slick if I could pull it off.

Honestly, this instructable could be a book if you wanted to flesh it out a little. Anyway, great job!